A Tip: Picture says to "bring some gold as you will be dying a lot" you dont need your gear, strip naked and retry until you get the wings, when you got them, equip your gear back. They will disappear, just use /reload and they will be back.

Seems this may have been fixed with the 5.4 patch. I've had the wings for about a week, then I logged in after the patch and they were gone. Tried getting them back using the method in op's post (how I got them in the first place) and it seems the glyph now properly transforms you into a Mantid for 5 minutes.

But just to be clear, we still can't skip the cinema, combo points go away on the adds in several new fights just like in every tier (pretty damned sure this happened on watchers), and I couldn't open the dungeon journal last night without reloading UI.